[Federal Register Volume 84, Number 131 (Tuesday, July 9, 2019)]
[Proposed Rules]
[Pages 32664-32667]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-14391]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0493; Product Identifier 2019-NM-043-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2011-18-15, which applies to certain Bombardier, Inc., Model DHC-8-400 
series airplanes. AD 2011-18-15 requires initial and repetitive torque 
checks of the bolt preload; detailed inspection of the barrel nuts and 
cradle for cracking, pitting, and corrosion if the bolt preload is 
correct; and replacement of hardware if necessary. Since the FAA issued 
AD 2011-18-15, the agency has determined that incorporation of a new 
design change is necessary to address the root cause of the failure of 
the barrel nuts. This proposed AD would retain the existing 
requirements and add new inspections and replacement of certain 
hardware, which would terminate the repetitive torque checks and 
inspections. This AD also removes airplanes from the applicability. The 
FAA is proposing this AD to address the unsafe condition on these 
products.

DATES: The FAA must receive comments on this proposed AD by August 23, 
2019.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact 
Bombardier, Inc., Q-Series Technical Help Desk, 123 Garratt Boulevard, 
Toronto, Ontario M3K 1Y5, Canada; phone: 416-375-4000; fax: 416-375-
4539; email: [email protected]; internet: http://www.bombardier.com. You may view this referenced service information at 
the FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, 
WA. For information on the availability of this material at the FAA, 
call 206-231-3195.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0493; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this NPRM, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations is listed above. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer, 
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7330; fax: 516-
794-5531; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2019-0493; 
Product Identifier 2019-NM-043-AD'' at the beginning of your comments. 
The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. The 
FAA will consider all comments received by the closing date and may 
amend this proposed AD based on those comments.
    The FAA will post all comments received, without change, to http://www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact received about this proposed AD.

Discussion

    The FAA issued AD 2011-18-15, Amendment 39-16797 (76 FR 54093, 
August 31, 2011) (``AD 2011-18-15''), for certain Bombardier, Inc., 
Model DHC-8-400 series airplanes. AD 2011-18-15 requires initial and 
repetitive torque checks of the bolt preload; detailed inspection of 
the barrel nuts and cradle for cracking, pitting, and corrosion if the 
bolt preload is correct; and replacement of hardware if necessary. AD 
2011-18-15 resulted from in-service reports of cracked barrel nuts 
found at the front spar locations of the wing-to-fuselage attachment 
joints, and reports of a loose washer in the barrel nut assembly. The 
FAA issued AD 2011-18-15 to address cracked barrel nuts and a loose 
washer in the barrel nut assembly, which could result in failure of the 
barrel nuts, compromising the structural integrity of the wing-to-
fuselage attachments, and possible separation of the wing from the 
airplane during flight.

Actions Since AD 2011-18-15 Was Issued

    Since the FAA issued AD 2011-18-15, the manufacturer has developed 
a design change (replacement of the existing wing front spar barrel 
nuts with new barrel nuts that are more resistant to hydrogen 
embrittlement, and installation of new bolts and pre-load indicating 
washers). The FAA has determined that the design change will address 
the root cause of the failure of the barrel nuts.
    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued Canadian AD

[[Page 32665]]

CF-2011-24R1, dated January 21, 2019 (referred to after this as the 
Mandatory Continuing Airworthiness Information, or ``the MCAI''), to 
correct an unsafe condition for certain Bombardier, Inc., Model DHC-8-
400 series airplanes. The MCAI states:

    There have been several in-service reports of cracked barrel 
nuts found at the front spar locations of the wing to fuselage 
attachment joints. Additionally, three operators have reported 
finding a loose washer in the barrel nut assembly. Failure of the 
barrel nuts could compromise the structural integrity of the wing to 
fuselage attachments.
    The investigation determined that these cracks are due to 
hydrogen embrittlement.
    The original version of this [Canadian] AD mandated initial and 
repetitive detailed inspections of the barrel nuts, part number (P/
N) DSC228-16.
    Since the original version of this [Canadian] AD, Bombardier 
Inc. has developed a design change to address the root cause of the 
failure of the barrel nuts. This design change replaces the existing 
wing front spar barrel nuts, P/N DSC228-16, with new Inconel 718 
barrel nuts, P/N B0203072-16S, which are more resistant to hydrogen 
embrittlement. The design change also includes new bolts and new 
pre-load indicating washers.
    Revision 1 of this [Canadian] AD mandates this design change as 
a terminating action to the repetitive inspection requirements of 
Part II of this [Canadian] AD. A torque verification has also been 
introduced to address loose washers in the barrel nut assembly.

    You may examine the MCAI in the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0493.

Related Service Information Under 1 CFR Part 51

    Bombardier has issued the following service information.
     Bombardier Alert Service Bulletin A84-57-25, Revision A, 
dated July 16, 2018. This service information describes procedures for 
initial and repetitive torque checks of the bolt preload, detailed 
inspection of the barrel nuts and cradle for cracking, pitting, and 
corrosion if the bolt preload is correct, and replacement of hardware 
if necessary.
     Bombardier Service Bulletin 84-57-26, Revision C, dated 
July 16, 2018. This service information describes procedures for a 
visual inspection of the saddle washer and retainer for any damage 
(cracks) and corrosion, and replacement of the existing wing front spar 
barrel nuts, bolts, and pre-load indicating washers.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in the ADDRESSES section.

FAA's Determination

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with the State of Design Authority, the FAA 
has been notified of the unsafe condition described in the MCAI and 
service information referenced above. The FAA is proposing this AD 
because the agency evaluated all the relevant information and 
determined the unsafe condition described previously is likely to exist 
or develop on other products of the same type design.

Proposed Requirements of This NPRM

    This proposed AD would retain all of the requirements of AD 2011-
18-15. This proposed AD would also require accomplishing the actions 
specified in the service information described previously, which would 
terminate the repetitive torque checks and inspections and the 
corrective actions for incorrect bolt preload.

Revised Applicability

    The FAA also revised the applicability of this AD from what was 
specified in AD 2011-18-15 to remove airplane serial numbers 4438 and 
subsequent. The terminating actions specified in this proposed AD are 
accomplished on those airplanes during production.

Costs of Compliance

    The FAA estimates that this proposed AD affects 54 airplanes of 
U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                      Estimated Costs for Required Actions
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Retained actions from AD                15 work-hours x $85 per          $10,492         $11,767        $635,418
 2011[dash]18[dash]15.                   hour = $1,275.
New proposed actions..................  15 work-hours x $85 per           10,492          11,767         635,418
                                         hour = $1,275.
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    The FAA has received no definitive data that would enable us to 
provide cost estimates for the on-condition repairs specified in this 
proposed AD.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes and associated appliances to the 
Director of the System Oversight Division.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866,
    2. Will not affect intrastate aviation in Alaska, and

[[Page 32666]]

    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by removing Airworthiness Directive (AD) 
2011-18-15, Amendment 39-16797 (76 FR 54093, August 31, 2011), and 
adding the following new AD:

    Bombardier, Inc.: Docket No. FAA-2019-0493; Product Identifier 
2019-NM-043-AD.

(a) Comments Due Date

    The FAA must receive comments by August 23, 2019.

(b) Affected ADs

    This AD replaces AD 2011-18-15, Amendment 39-16797 (76 FR 54093, 
August 31, 2011) (``AD 2011-18-15'').

(c) Applicability

    This AD applies to Bombardier, Inc., Model DHC-8-400, -401, and 
-402 airplanes, certificated in any category, serial numbers 4001 
through 4437 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Reason

    This AD was prompted by in-service reports of cracked barrel 
nuts found at the front spar locations of the wing-to-fuselage 
attachment joints, and a loose washer in the barrel nut assembly. 
The FAA is issuing this AD to address cracked barrel nuts and a 
loose washer in the barrel nut assembly, which could result in 
failure of the barrel nuts, compromising the structural integrity of 
the wing-to-fuselage attachments, and possible separation of the 
wing from the airplane during flight.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Retained Initial and Repetitive Inspections, With Revised Service 
Information

    This paragraph restates the requirements of paragraph (g) of AD 
2011-18-15, with revised service information. At the applicable time 
specified in paragraph (g)(1) or (g)(2) of this AD: Do a torque 
check to determine if the bolt preload is correct, and if the 
preload is correct, before further flight, do a detailed inspection 
of each barrel nut and cradle for cracking, pitting or corrosion, in 
accordance with paragraph 3.B., part A, of the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-25, dated 
July 20, 2011; or Bombardier Alert Service Bulletin A84-57-25, 
Revision A, dated July 16, 2018. After the effective date of this 
AD, only Bombardier Alert Service Bulletin A84-57-25, Revision A, 
dated July 16, 2018, may be used. Repeat the torque check and, as 
applicable, the inspection thereafter at intervals not to exceed 
2,000 flight hours or 12 months, whichever occurs first.
    (1) For airplanes that have accumulated 1,900 or more total 
flight hours as of September 15, 2011 (the effective date of AD 
2011-18-15), or for which it has been 12 months or more since the 
date of issuance of the original Canadian airworthiness certificate 
or the date of issuance of the original Canadian export certificate 
of airworthiness as of September 15, 2011: Within 100 flight hours 
or 10 days after September 15, 2011, whichever occurs first.
    (2) For airplanes that have accumulated less than 1,900 total 
flight hours as of September 15, 2011 (the effective date of AD 
2011-18-15), and for which it has been less than 12 months since the 
date of issuance of the original Canadian airworthiness certificate 
or the date of issuance of the original Canadian export certificate 
of airworthiness as of September 15, 2011: Prior to the accumulation 
of 2,000 total flight hours or within 12 months since the date of 
issuance of the original Canadian standard airworthiness certificate 
or the date of issuance of the original Canadian export certificate 
of airworthiness, whichever occurs first.

(h) Retained Corrective Actions for Incorrect Bolt Preload, With 
Revised Service Information

    This paragraph restates the requirements of paragraph (h) of AD 
2011-18-15, with revised service information. If any bolt preload is 
found to be incorrect (i.e., the ring can be rotated during any 
torque check required by paragraph (g) of this AD), before further 
flight, replace all hardware at that location (except the saddle 
washer and retainer) in accordance with paragraph 3.B., part B, of 
the Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-57-25, dated July 20, 2011; or paragraph 3.B. of the 
Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, 
Revision C, dated July 16, 2018. After the effective date of this 
AD, only Bombardier Service Bulletin 84-57-26, Revision C, dated 
July 16, 2018, may be used.

(i) Retained Corrective Actions for Barrel Nut/Cradle Discrepancies, 
With Revised Service Information

    This paragraph restates the requirements of paragraph (i) of AD 
2011-18-15, with revised service information. If any crack, pitting, 
or corrosion of the barrel nut or cradle is found during any 
inspection required by paragraph (g) of this AD, before further 
flight, replace all hardware at that location (except the saddle 
washer and retainer) in accordance with paragraph 3.B., part B, of 
the Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-57-25, dated July 20, 2011; or paragraph 3.B. of the 
Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, 
Revision C, dated July 16, 2018. After the effective date of this 
AD, only Bombardier Service Bulletin 84-57-26, Revision C, dated 
July 16, 2018, may be used.

(j) New Requirement of This AD: Replacement and Visual Inspection

    Within 12,000 flight hours or 72 months after the effective date 
of this AD, whichever occurs first: Do a visual inspection of the 
saddle washer and retainer for any damage (cracks) or corrosion; and 
replace the wing front spar barrel nuts, bolts, and pre-load 
indicating washers; in accordance with paragraph 3.B. of the 
Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, 
Revision C, dated July 16, 2018.

(k) New Corrective Actions for Damage (Cracks) or Corrosion

    If any damage (cracks) or corrosion is found during any 
inspection required by paragraph (j) of this AD: Before further 
flight, accomplish corrective actions in accordance with the 
procedures specified in paragraph (p)(2) of this AD.

(l) New Provision of This AD: Terminating Actions for Repetitive Torque 
Checks and Detailed Inspections

    Accomplishment of the applicable actions required by paragraphs 
(j) and (k) of this AD, at all four barrel nut locations, terminates 
the repetitive torque checks and detailed inspections of paragraph 
(g) of this AD.

(m) Parts Installation Prohibition

    As of the effective date of this AD, no person may install, on 
any airplane, a barrel nut having part number DSC228-16.

(n) Retained Special Flight Permit Provisions, With No Changes

    This paragraph restates the requirements of paragraph (k) of AD 
2011-18-15, with no changes. Special flight permits, as described in 
14 CFR 21.197 and 21.199, may be issued to operate the airplane to a 
location where the requirements of this AD can be accomplished, but 
concurrence by the Manager, New York ACO Branch, FAA, is required 
before issuance of the special flight permit. Before using any 
approved special flight permits, notify your principal maintenance 
inspector (PMI) or principal avionics inspector (PAI), as 
appropriate, or lacking a principal inspector, your local Flight 
Standards District Office (FSDO). Operators must request a repair 
drawing from

[[Page 32667]]

Bombardier, which provides recommendations for a one-time special 
flight permit. The repair drawing will be applicable to the 
operator's aircraft serial number only. Special flight permits may 
be permitted provided that the conditions specified in paragraphs 
(n)(1), (n)(2), (n)(3), (n)(4), and (n)(5) of this AD are met.
    (1) Only one barrel nut out of four is cracked, one cradle is 
cracked, or one washer is loose; all other strut (wing front spar) 
bolt locations must be free of damage.
    (2) The airplane must operate with reduced airspeed not to 
exceed 180 KIAS (knots indicated air speed). No passengers and no 
cargo are onboard.
    (3) The airplane must not operate in known or forecast 
turbulence, other than light turbulence.
    (4) The airplane descent rate on landing flare-out is not to 
exceed 5 feet per second.
    (5) Heavy braking or hard turning of the airplane upon landing 
is to be avoided if possible.

(o) Credit for Previous Actions

    (1) This paragraph restates the provisions of paragraph (j) of 
AD 2011-18-15, with revised formatting and updated service 
information. This paragraph provides credit for torque checks, 
initial inspections, and replacements required by paragraphs (g) and 
(h) of this AD, if those actions were performed before the effective 
date of this AD using the service information specified in 
paragraphs (o)(1)(i) through (o)(1)(v) of this AD, which is not 
incorporated by reference in this AD. The repetitive inspections 
required by paragraph (g) of this AD must be continued at the time 
specified.
    (i) Bombardier Alert Service Bulletin A84-57-19, dated February 
1, 2008.
    (ii) Bombardier Alert Service Bulletin A84-57-19, Revision A, 
dated February 6, 2008.
    (iii) Bombardier Alert Service Bulletin A84-57-19, Revision B, 
dated March 6, 2008.
    (iv) Bombardier Alert Service Bulletin A84-57-19, Revision C, 
dated August 20, 2008.
    (v) Bombardier Alert Service Bulletin A84-57-19, Revision D, 
dated August 12, 2011.
    (2) This paragraph provides credit for the actions required by 
paragraphs (h), (i), (j), and (k) of this AD, if those actions were 
performed before the effective date of this AD using the service 
information specified in paragraphs (o)(2)(i) through (o)(2)(iii) of 
this AD. This service information is not incorporated by reference 
in this AD.
    (i) Bombardier Service Bulletin 84-57-26, dated March 21, 2013.
    (ii) Bombardier Service Bulletin 84-57-26, Revision A, dated 
July 18, 2014.
    (iii) Bombardier Service Bulletin 84-57-26, Revision B, dated 
February 26, 2015.
    (3) This paragraph provides credit for the actions required by 
paragraphs (h) and (i) of this AD, if those actions were performed 
before the effective date of this AD using the service information 
specified in paragraphs (o)(3)(i) and (o)(3)(ii) of this AD.
    (i) Bombardier Alert Service Bulletin A84-57-25, dated July 20, 
2011, which was incorporated by reference in AD 2011-18-15.
    (ii) Bombardier Alert Service Bulletin A84-57-25, Revision A, 
dated July 16, 2018, which is incorporated by reference in this AD.

(p) Other FAA AD Provisions

    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York ACO Branch, FAA, has the authority to approve AMOCs for this 
AD, if requested using the procedures found in 14 CFR 39.19. In 
accordance with 14 CFR 39.19, send your request to your principal 
inspector or local Flight Standards District Office, as appropriate. 
If sending information directly to the manager of the certification 
office, send it to ATTN: Program Manager, Continuing Operational 
Safety, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: 516-228-7300; fax: 516-794-5531. Before 
using any approved AMOC, notify your appropriate principal 
inspector, or lacking a principal inspector, the manager of the 
local flight standards district office/certificate holding district 
office.
    (2) Contacting the Manufacturer: For any requirement in this AD 
to obtain corrective actions from a manufacturer, the action must be 
accomplished using a method approved by the Manager, New York ACO 
Branch, FAA; or Transport Canada Civil Aviation (TCCA); or 
Bombardier, Inc.'s TCCA Design Approval Organization (DAO). If 
approved by the DAO, the approval must include the DAO-authorized 
signature.
    (3) AMOCs approved previously for AD 2011-18-15 are approved as 
AMOCs for the corresponding provisions of this AD.

(q) Related Information

    (1) Refer to Mandatory Continuing Airworthiness Information 
(MCAI) Canadian AD CF-2011-24R1, dated January 21, 2019, for related 
information. This MCAI may be found in the AD docket on the internet 
at http://www.regulations.gov by searching for and locating Docket 
No. FAA-2019-0493.
    (2) For more information about this AD, contact Andrea Jimenez, 
Aerospace Engineer, Airframe and Propulsion Section, FAA, New York 
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: 516-228-7330; fax: 516-794-5531; email: [email protected].
    (3) For service information identified in this AD, contact 
Bombardier, Inc., Q-Series Technical Help Desk, 123 Garratt 
Boulevard, Toronto, Ontario M3K 1Y5, Canada; phone: 416-375-4000; 
fax: 416-375-4539; email: [email protected]; internet: 
http://www.bombardier.com. You may view this service information at 
the FAA, Transport Standards Branch, 2200 South 216th St., Des 
Moines, WA. For information on the availability of this material at 
the FAA, call 206-231-3195.


    Issued in Des Moines, Washington, on June 28, 2019.
Dionne Palermo,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-14391 Filed 7-8-19; 8:45 am]
 BILLING CODE 4910-13-P